A Cryogenic Positive-Displacement Auxiliary Power Unit for Space Vehicles

For auxiliary power system applications in space, a cryogenic, positive-displacement power system has been developed. This system consists of an internal combustion engine using hydrogen as the fuel and oxygen as the oxidizer. This type of engine offers the lowest fixed weight of any space power unit under current development and provides for a very low specific propellant combustion. The engine, in turn, would provide electric and hydraulic power sources.